BLU-554 is an orally available, potent, irreversible inhibitor of FGFR4. BLU-554 was specifically designed by Blueprint Medicines to inhibit FGFR4 with exquisite selectivity, thereby sparing the paralogs FGFR1, FGFR2 and FGFR3. Blueprint Medicines is developing BLU-554, an investigational medicine, for the treatment of patients with FGFR4-activated HCC. Blueprint Medicines estimates that approximately 30 percent of patients with HCC have tumors with aberrantly activated FGFR4 signaling. The FDA has granted orphan drug designation to BLU-554.